Can new bones grow with sound wave stimulation? Only 10 minutes a day, stem cells differentiate rapidly in 5 days, and the chip device only costs $1

Fengse from Aofei Temple
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Bone regeneration has always been a focus of attention in the field of regenerative medicine.

Recently, some scientists have successfully differentiated stem cells into bone cells through high-frequency sound wave treatment .

This method can not only shorten the treatment time - the researchers completed the transformation in just 5 days, but also reduce the pain of patients - the required stem cells can be extracted from fat instead of bone marrow.

△ The green part is the transformed bone cell, magnification: 60

Currently, this achievement has been published in the materials journal Small, and the researchers are from the Royal Melbourne Institute of Technology.

10 minutes of high-frequency sound wave stimulation every day

A key challenge in bone regeneration is obtaining large numbers of osteocytes.

Fortunately, direct external physical stimulation can induce stem cells to respond accordingly and achieve differentiation into bone cells.

However, scientists have always tried to use low-frequency sound waves (<1kHz) to complete this stimulation process, which usually requires at least 7 consecutive days .

In this study, scientists used 10MHz nano-amplitude high-frequency sound waves for 10 minutes a day for 5 consecutive days to successfully induce mesenchymal stem cells (MSCs) to differentiate into bone cells.

Specifically, it is manifested by the significant upregulation of early osteogenic markers (RUNX2, COL1A1) and the sustained increase of late markers (osteocalcin, osteopontin) .

The figure below shows the results on day 3, presented as fluorescent images, where the first row is the control group, the second row is the experimental group, and green represents the expression of RUNX2 and COL1A1.

The MSC stem cells used in the experiment can be extracted not only from bone marrow but also from fat, thus reducing the physical pain and psychological pressure of patients from multiple bone marrow cell extractions.

In addition, this method does not require the addition of additional "bone-inducing" drugs to ensure the safety of the cells. They can be directly injected into the injured area or applied to implants to test bone regeneration.

The high-frequency sound waves used in the experiment were generated on a low-cost microchip device developed by the researchers , which can apply the right amount of pressure to the cells in the right place to trigger the differentiation process.

The specific device is also very simple :

High-frequency sound waves of 10 MHz (green part) are emitted through interdigital transducers (IDTs) photolithographically formed on a lithium niobate crystal (LiNbO3) substrate , and cells are induced to differentiate in a thin layer of silicone oil in a glass culture dish.

Looks quite small and portable.

Moreover, according to the researchers, the chip costs only $1 - while previous low-frequency sound wave conversion methods used equipment that was large in size, complicated to operate, and quite expensive, making it difficult to mass-produce and apply to clinical practice.

Professor Leslie Yeo, corresponding author of the paper, added:

He and his team have spent the past decade studying the interaction between high-frequency sound waves and different materials.

Such devices can now be easily scaled up to facilitate more efficient stem cell differentiation processes.

Therefore, their next plan is to improve the device so that it can be scaled up to a more practical converter.

Paper address:
https://onlinelibrary.wiley.com/doi/10.1002/smll.202106823

Reference link:
https://www.rmit.edu.au/news/all-news/2022/feb/sound-waves-stem-cells